Natural Incubation. 
21 
All eggs undergoing the process of incubation should be examined by the aid of a light at the expiration 
of from five to nine days, as unfertile ones can be detected, and are perfectly good for puddings, cakes, etc. ; 
and, if two hens are now sitting at the same time, the fertile eggs may be given to one and a fresh sitting 
supplied to the other. To test eggs, obtain a piece of stout cardboard about 6x5 inches, cutting a hole in 
the centre similar to an egg in shape, but a quarter of an inch smaller than an average one, and tack a piece 
of light wood across the bottom of the cardboard underneath the hole made, with a slight hollow cut out of 
the uppermost side to act as a rest (see Fig. 18). Place the egg to be tested on the wooden rest, and hold 
the cardboard between yourself and the light (a lantern is best), when, at the expiration of from five to seven 
days sitting, the merest novice will discover whether incubation has begun or not. With practice it is possible to 
discern whether an egg is fertile or not at the third day, as there is, even at this early stage, a marked differ- 
ence between a sterile egg and one containing an embryo chicken. By taking up a perfectly fresh new-laid 
egg and placing it under the same examination it will be found quite clear, but if sat upon for three or four 
days and fertile the difference becomes apparent. With a little practice fertile eggs may be detected instantly 
and with positive certainty, and after the ninth or tenth day no mistake is ever likely to occur. It docs not 
follow that eggs at this stage, though fertile, will always hatch ; many different things may arise to upset 
calculations between the time of examination and date of hatching. This is but given as a guide to obviate 
the possibility of the hen sitting on eggs which contain no germ of life. 
The fertility of eggs will greatly depend upon the number of hens allowed each cock, and to surrounding 
circumstances ; thus, if kept in a small and confined space, a few hens (three or four) will give the highest 
results, but if given free range the number may be considerably increased. The different varieties vary to a 
great extent in their habits. A lively, active bird, such as the Leghorn, Game, or Hamburg, would be able 
to attend to more hens than a Langshan, Brahma, or Cochin in the same space ; and in every case a healthy, 
vigorous cockerel of any of the breeds will be found more reliable in fertilising the eggs than an old cock of 
the same breed. A little attention to the appearance of the hens will be a good guide, as if they are found to 
be devoid of feathers on the back, more hens is the remedy. Most beginners are, however, likely to err on the 
other side, by allowing too many hens to the cock, and many unfertile eggs is the natural outcome. Practical 
experience and observation are the best teachers, though, as a guide, it will be .safe to allow the heavy 
varieties— Malays, Dorkings, Cochins, etc. — three or four hens if kept in a confined space, and to increase 
the number of hens up to ten or twelve if free and unlimited range is allowed. For the lively and active 
breeds — Minorcas, Ilamburgs, Leghorns, etc.— six or seven in narrow limits will be found enough, but in a 
large and unlimited run twenty hens may be placed with one cock or cockerel. As a noticeable fact, and 
one taken great advantage of by Breeders of Exhibition Poultry, the fewer hens placed with a vigorous 
cockerel or two-year-old cock the more cockerels may be anticipated, and the more hens given the same birds 
will be found to produce a majority of pullets in the progeny. Another point to remember, when purchasing 
eggs for incubation, is the fact that sterile or barren eggs remain a clear yellow to the last, and if fertile, even 
if they do not hatch, will be found on examination to explode, or are decomposed to some extent. This is 
accounted for in many ways, such as getting chilled in the earlier stages of incubation, or being fouled or 
Fig. 18. — Egg Tester, made of cardboard. 
